Felling work vehicle

Abstract

Provided is a felling work vehicle that can safely fell a cut standing tree in a stable direction. The present invention is a felling work vehicle (1) that fells a standing tree, the felling work vehicle (1) being characterized by comprising: a vehicle body (2); traveling devices (4); a rotating frame (6) disposed between the traveling devices and provided with a recess (6a) for receiving, from the front side, the standing tree to be felled; a grapple device (8) connected to the rotating frame and provided with a grapple that holds the standing tree to be felled with the standing tree being received in the recess of the rotating frame; and a cutting device (12) that cuts the standing tree held by the grapple device, the standing tree being cut below the grapple. The rotating frame is attached to the vehicle body so as to be rotatable around a rotation axis (6b), the rotation axis is positioned further to the front side of the vehicle body than the standing tree held by the grapple device, and through rotation of the rotating frame, the standing tree that was cut is felled toward the front of the vehicle body.

Description

Felling vehicle

[0001] The present invention relates to a felling vehicle, and more particularly to a felling vehicle for felling standing trees.

[0002] Japanese Patent No. 7125330 (Patent Document 1) describes a self-propelled timber felling and transporting machine. This self-propelled timber felling and transporting machine is equipped with a rotating frame equipped with a grapple device having a pair of grapples for holding and holding standing trees from the sides, a cutting device for cutting standing trees from the sides in order to fell them, and a device for rotating the rotating frame between vertical and horizontal positions for the grapple device and the cutting device, and is configured so that after felling, the grapple of the grapple device carries out the felled trees as the timber felling and transporting machine travels.

[0003] In this self-propelled timber felling and transporting machine, the tree to be felled is held by the grapple device from the side, and then cut from the side by the cutting device. After the tree is cut, the rotating frame is rotated from a vertical position to a horizontal position with the cut tree still held by the grapple device, and the timber is transported by moving the traveling body.

[0004] Patent No. 7125330

[0005] However, the self-propelled timber felling and transporting machine described in Patent Document 1 has a problem in that when felling a cut tree while held by the grapple device, the direction in which the tree falls is unstable. That is, when a tree held by the grapple device falls, the lower stump and the cut upper part come into contact with each other, causing the fulcrum of the fallen tree to be unstable and potentially falling in an unintended direction. Furthermore, depending on the diameter of the tree being felled and the slope of the land where the felling operation is being performed, a force acting in an upward direction may act on the fallen tree, lifting the felling and transporting machine along with the grapple device holding the tree, causing the front of the felling and transporting machine to lift up. To prevent this lifting of the felling and transporting machine, the felling and transporting machine must have a certain size and mass, making it difficult to reduce the size and weight of the felling and transporting machine.

[0006] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a felling vehicle that can fell cut trees safely and in a stable direction.

[0007] In order to solve the above-mentioned problems, the present invention provides a felling work vehicle for felling standing trees, comprising a vehicle body, a pair of running devices provided on both sides of the vehicle body in the width direction, a rotating frame arranged between the running devices and provided with a recess for receiving the tree to be felled from the front, a grapple device connected to the rotating frame and equipped with a grapple for embracing the tree to be felled received in the recess of the rotating frame from the side, and a cutting device for cutting the tree held by the grapple device below the grapple, wherein the rotating frame is attached to the vehicle body so as to be rotatable around a rotation axis extending in the width direction of the vehicle body, and the rotation axis is positioned so as to be located further forward of the vehicle body than the standing tree held by the grapple device, and by rotating the rotating frame, the cut tree is lifted and felled toward the front of the vehicle body.

[0008] In the present invention configured as described above, the tree to be felled is received in the recess of the rotating frame and held by the grapple device. The held tree is then cut below the grapple by the cutting device. After cutting, the rotating frame is rotated about the rotation axis while the grapple device is still holding the tree, and the cut tree is felled toward the front of the vehicle body.

[0009] According to the present invention configured as described above, the rotation axis about which the rotating frame rotates when felling a tree is located further forward of the vehicle body than the tree held by the grapple device. Therefore, the cut tree is lifted upward from the stump by the rotation of the rotating frame, and the tree held by the grapple device falls reliably with the rotation axis of the rotating frame as a fulcrum. As a result, the direction in which the cut tree falls is stable, allowing for safe felling operations.

[0010] In the present invention, it is preferable that the vehicle further includes a pivoting arm that supports a grapple device, the pivoting arm being rotatably attached to the pivoting frame around an axis extending in the width direction of the vehicle body, and supporting the grapple device above the pivoting frame.

[0011] According to the present invention configured in this manner, the grapple device is supported by a pivoting arm that can rotate around an axis extending in the width direction of the vehicle body, so that the grapple of the grapple device can be applied at almost a right angle to standing trees growing on slopes, allowing the standing trees to be securely held by the grapple device.

[0012] In the present invention, it is preferable that the vehicle further includes a pivoting arm that supports the grapple device, and this pivoting arm is rotatably attached to the pivoting frame around an axis extending in the fore-and-aft direction of the vehicle body, and supports the grapple device above the pivoting frame.

[0013] According to the present invention configured in this manner, the grapple device is supported by a pivoting arm that can rotate around an axis extending in the fore-and-aft direction of the vehicle body, so that the grapple of the grapple device can be placed at almost a right angle even against standing trees growing on slopes that incline in the left-right direction of the vehicle body, allowing the standing trees to be securely held by the grapple device.

[0014] In the present invention, the grapple device is preferably attached to the rotating arm via a universal support mechanism, and the universal support mechanism allows the grapple device to rotate about a predetermined axis relative to the rotating arm.

[0015] According to the present invention configured in this manner, the flexible support mechanism allows the grapple device to rotate relative to the pivoting arm, so that the orientation of the grapple device can be easily adapted to the direction of the standing tree to be held, thereby ensuring secure holding of the tree.

[0016] In the present invention, preferably, the universal support mechanism elastically supports the grapple device so as to allow the grapple device to rotate about a predetermined axis relative to the rotating arm.

[0017] According to the present invention configured as described above, the universal support mechanism elastically supports the grapple device to allow it to rotate, and an elastic force acts on the grapple device to return it to its original direction. As a result, after the tree held by the grapple device is cut, the grapple device returns to its original direction due to the elastic force, making it possible to stabilize the direction of the tree being held.

[0018] In the present invention, the rotating arm is preferably configured to be extendable so that the grapple device can move away from the rotating frame.

[0019] According to the present invention configured in this manner, the pivot arm is extendable and the grapple device is separated from the pivot frame, so that when a felled tree is transported, the base of the tree is farther away from the front of the felling vehicle. As a result, when the felling vehicle transporting the tree turns, the front of the felling vehicle is less likely to interfere with the base of the tree, making transport work easier.

[0020] In the present invention, the cutting device is preferably configured to cut the standing tree to be felled below the pivot axis.

[0021] According to the present invention configured in this way, the cutting device cuts the tree to be felled below the pivot axis, so even if the tree is thick, the cut tree is reliably lifted above the stump when felling, reliably preventing contact between the cut tree and the stump. This makes it possible to more steadily fell the tree.

[0022] In the present invention, it is preferable that the machine further includes a torque application device, which, when felling a tree cut by rotating the rotating frame, applies a torque to the rotating frame in the opposite direction to the direction in which the tree falls, thereby slowing down the speed at which the tree falls.

[0023] According to the present invention configured in this manner, the torque application device reduces the speed at which the tree falls, allowing the cut tree to fall slowly, preventing the occurrence of vehicle tipping over accidents or damage to the device due to the reaction force acting on the felling vehicle when felling.

[0024] In the present invention, it is preferable that a winch be further provided to assist the traveling device in traveling, and the drum of this winch is configured to pay out or wind up the wire rope in synchronization with the traveling device.

[0025] According to the present invention configured in this manner, the winch drum pays out or winds up the wire rope in synchronization with the traveling device, so when the felling vehicle travels with the assistance of the winch, it is possible to prevent the wire rope from becoming significantly slack or one end of the felling vehicle from being pulled up by the wire rope, allowing the felling vehicle to travel stably.

[0026] In the present invention, it is preferable that the vehicle further comprises a prime mover that generates power to operate the traveling device, and the prime mover is supported on the vehicle body so as to be rotatable about a substantially horizontal axis.

[0027] According to the present invention configured in this manner, the prime mover is supported on the vehicle body so that it can rotate about an approximately horizontal axis. Therefore, even when felling work is performed on slopes using a felling vehicle, the prime mover can be maintained in a nearly horizontal position, allowing the prime mover to operate reliably.

[0028] In the present invention, the cutting device is preferably a chainsaw pivotally mounted on a pivoting frame.

[0029] According to the present invention configured in this manner, since the cutting device is a chainsaw, it is possible to cut tree species that cannot be cut with a cutter blade, and the cutting device can be made lighter.

[0030] In the present invention, the grapple device is preferably configured to be able to hold the tree to be felled while maintaining the rotating frame approximately parallel to the slope, even when the tree is growing on an uphill or downhill slope, and the cutting device is configured to cut the tree in a plane approximately parallel to the rotating frame.

[0031] According to the present invention configured in this way, even when a tree is growing on an upslope or downslope, the grapple device is configured to be able to hold the tree while maintaining the rotating frame approximately parallel to the slope, so that even when the tree is growing on a slope, the tree can be cut at a low position approximately parallel to the slope. As a result, the height of the stump after felling the tree can be kept low, and after felling the tree, the stump is less likely to get in the way when felling the next tree, allowing the felling operation to proceed smoothly.

[0032] In the present invention, preferably, the grapple device is configured to be able to hold the tree to be felled even when the tree is growing on a slope that inclines to the left and right of the vehicle body, and the cutting device is configured to cut the tree held by the grapple device.

[0033] According to the present invention configured in this manner, even standing trees growing on a slope that inclines to the left and right of the vehicle body can be held by the grapple device, so felling operations can be carried out without aligning the fore-and-aft direction of the vehicle body with the inclination direction of the slope, allowing the felling operation to proceed smoothly.

[0034] In the present invention, preferably, the grapple device is configured to be able to hold a standing tree to be felled even when the standing tree is growing on a slope that is inclined in the fore-and-aft direction of the vehicle body and also in the left-and-right direction of the vehicle body, and the cutting device is configured to cut the standing tree held by the grapple device.

[0035] According to the present invention configured in this way, standing trees can be held even when they are growing on a slope that is inclined (upward or downward) in the fore-and-aft direction of the vehicle body and also inclined left and right.Therefore, in most cases, felling operations can be performed without aligning the direction of the slope with the direction of the vehicle body, allowing the felling operation to proceed smoothly.

[0036] The felling vehicle of the present invention can fell cut trees safely and in a stable direction.

[0037] 6A and 6B are a side view and a top view of a felling vehicle according to a first embodiment of the present invention; a front view of a felling vehicle according to a first embodiment of the present invention; an enlarged view showing a rotating frame and its drive mechanism provided on the felling vehicle according to a first embodiment of the present invention; a front view showing an enlarged view of a grapple device and the like provided on the felling vehicle according to a first embodiment of the present invention; a top view showing a grapple device provided on the felling vehicle according to a first embodiment of the present invention in an open state; a top view showing a grapple device provided on the felling vehicle according to a first embodiment of the present invention in a state where it is holding a standing tree; a top view showing a grapple device provided on the felling vehicle according to a first embodiment of the present invention in a folded state; a cross-sectional view taken along line IX-IX in FIG. 6A and 6B of the felling vehicle according to a first embodiment of the present invention; and a diagram showing the procedure for felling and transporting a standing tree on flat ground using the felling vehicle according to a first embodiment of the present invention. FIG. 1 is a diagram showing the procedure for felling and transporting a standing tree on flat ground using a felling vehicle of a first embodiment of the present invention. FIG. 2 is a diagram showing the procedure for felling and transporting a standing tree on flat ground using a felling vehicle of a first embodiment of the present invention. FIG. 3 is a diagram showing the procedure for felling and transporting a standing tree on flat ground using a felling vehicle of a first embodiment of the present invention. FIG. 4 is a diagram showing the procedure for felling and transporting a standing tree on flat ground using a felling vehicle of a first embodiment of the present invention. FIG. 5 is a diagram showing the procedure for felling a standing tree on an uphill slope using a felling vehicle of a first embodiment of the present invention. FIG. 6 is a diagram showing the procedure for felling a standing tree on an uphill slope using a felling vehicle of a first embodiment of the present invention. FIG. 7 is a diagram showing the procedure for felling a standing tree on a downhill slope using a felling vehicle of a first embodiment of the present invention. 1 is a diagram showing the procedure for felling trees on a downward slope using a felling vehicle according to a first embodiment of the present invention, and FIG. 2 is a side view of a felling vehicle according to a second embodiment of the present invention, showing the range in which the pivoting frame can be rotated.FIG. 1 is a side view of a felling vehicle according to a second embodiment of the present invention, showing the range of rotation of the pivot arm in the pitch direction. FIG. 2 is a front view of a felling vehicle according to a second embodiment of the present invention. FIG. 3 is an enlarged side view of a connecting portion between a pivot frame and a pivot arm in a felling vehicle according to a second embodiment of the present invention. FIG. 4 is a side view of a swing pin connecting a pivot frame and a pivot arm provided in a felling vehicle according to a second embodiment of the present invention. FIG. 5 is a top view of a swing pin connecting a pivot frame and a pivot arm provided in a felling vehicle according to a second embodiment of the present invention. FIG. 6 is a front view of a swing pin connecting a pivot frame and a pivot arm provided in a felling vehicle according to a second embodiment of the present invention. FIG. 7 is a diagram illustrating the felling of a standing tree on a slope with a lateral gradient using a felling vehicle according to a second embodiment of the present invention. FIG. 8 is a diagram illustrating the felling of a standing tree on a downward slope using a felling vehicle according to a second embodiment of the present invention. FIG. 9 is a diagram illustrating the felling of a standing tree on an uphill slope using a felling vehicle according to a second embodiment of the present invention.

[0038] Next, a felling vehicle according to a first embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a side view of the felling vehicle according to the first embodiment of the present invention. Fig. 2 is a top view of the felling vehicle according to the first embodiment of the present invention. Fig. 3 is a front view of the felling vehicle according to the first embodiment of the present invention. Fig. 4 is an enlarged view showing a rotating frame and its drive mechanism provided in the felling vehicle according to the first embodiment of the present invention.

[0039] 1 and 2, a felling work vehicle 1 according to a first embodiment of the present invention comprises a vehicle body 2, a pair of traveling devices 4 provided on both sides of the vehicle body 2 in the width direction, and a rotating frame 6 disposed between the traveling devices 4. A grapple device 8 for holding a standing tree to be felled is connected to the rotating frame 6 via a rotating arm 10. A chainsaw 12 (FIG. 2) is also attached to the rotating frame 6 as a cutting device for cutting the standing tree held by the grapple device 8. A winch 14 (FIG. 3) for towing the vehicle body is provided on each side of the vehicle body 2, and an engine 15 is mounted at the rear of the vehicle body 2 as a prime mover for generating power to operate the traveling devices 4 and the like.

[0040] As shown in Figure 2, the vehicle body 2 has a generally H-shaped frame in top view, and includes two vertical members 2a extending parallel to the front-to-rear direction of the felling vehicle 1 and a horizontal member 2b extending widthwise between the vertical members 2a. These vertical members 2a and horizontal members 2b extend generally horizontally. Furthermore, as shown in Figure 3, two connecting members 2c extend diagonally downward from both ends of the horizontal member 2b in a V-shape, connecting the horizontal member 2b to the vertical members 2a on both sides. This ensures a height H (Figure 3) of approximately 520 mm from the ground surface of the felling vehicle 1 to the horizontal members 2b, allowing for smooth felling and transport up and down the slope during row thinning.

[0041] In this specification, terms indicating directions such as front-rear, up-down, horizontal, and vertical indicate the respective directions when the felling vehicle 1 in the standard state shown in Fig. 1 is placed on horizontal ground. In this embodiment, the right side of Fig. 1 is the front side of the felling vehicle 1, and the left side is the rear side of the felling vehicle 1.

[0042] As shown in FIG. 2, the traveling devices 4 are provided on both sides of the vehicle body 2 in the width direction along each of the vertical members 2a. That is, as shown in FIG. 1, the traveling devices 4 include front driven wheels 4a rotatably mounted on the front end of each vertical member 2a, rear driven wheels 4b rotatably mounted on the rear end of each vertical member 2a, and drive sprockets 4c mounted on the upper end of each connecting member 2c. Furthermore, the front driven wheels 4a, rear driven wheels 4b, and drive sprockets 4c are arranged in a triangular shape in a side view, and crawlers 4d are wound around them in a triangular shape. This reduces slack in the crawlers 4d during both forward and reverse travel. Each drive sprocket 4c is connected to a traveling motor 4e (FIG. 2) driven by hydraulic pressure generated by the engine 15.

[0043] The traveling device 4 rotates and drives each drive sprocket 4c with a travel motor 4e, thereby enabling the felling vehicle 1 to move forward, backward, and turn. In this embodiment, each drive sprocket 4c is driven independently, allowing for on-the-spot turning using a skid steer system. The felling vehicle 1 of this embodiment has a total length of approximately 3700 mm, a total height of approximately 1520 mm, a total width of approximately 2200 mm, and a weight of approximately 3.0 t. As a result, the ground pressure of the felling vehicle 1 is approximately 135 g / cm 2 This means that the vehicle can travel uphill with little sinking even on fragile soil such as the black soil that makes up the majority of Japan's forests. The felling vehicle 1 of this embodiment can also climb slopes with an incline of approximately 45 degrees. Note that although a crawler type is used for the traveling device 4 in this embodiment, wheels can also be used for the traveling device 4.

[0044] 3, a pole 2d is provided at each end of the horizontal member 2b, extending vertically upward. A light 5a, a speaker 5b, a safety light 5c, and a vehicle-side camera 5d are provided on the pole 2d. Furthermore, a close-up camera 5e is provided on the top of the grapple device 8.

[0045] The lights 5a are configured to irradiate light toward the front and rear of the felling vehicle 1. In this embodiment, a total of eight lights are provided, four of which irradiate light toward the front of the felling vehicle 1 and four of which irradiate light toward the rear (only four lights are shown in FIG. 3).

[0046] The speaker 5b is provided to allow the voice of a worker performing tree felling work from a remote location to be output from the felling vehicle 1. As will be described later, the worker performing the tree felling work operates the felling vehicle 1 from a remote location using a controller (not shown) at hand. The speaker 5b is configured to output voice signals picked up by a microphone (not shown) on the controller (not shown) from the felling vehicle 1. This makes it possible to easily transmit instructions and the like from the worker operating the controller (not shown) to other workers who are relatively close to the felling vehicle 1.

[0047] The safety light 5c changes color depending on the status of the work being performed by the felling vehicle 1, informing nearby workers of the situation and urging their attention. For example, if any abnormality is detected, the safety light 5c lights up red. The vehicle-mounted camera 5d is configured to capture images of the area around the felling vehicle 1 and display the captured images on a controller (not shown) held by the worker. The vehicle-mounted camera 5d is mounted so that it can rotate around a vertical axis, allowing it to capture images of the area in front of and behind the felling vehicle 1. This allows the worker to remotely operate the felling vehicle 1 while accurately understanding the situation around them.

[0048] The close-up camera 5e is mounted on top of the grapple device 8 and is configured to capture images of the tree or other object to be felled. This allows the worker to accurately grasp the condition of the tree or object to be felled, and the tree can be securely held by the grapple device 8 even when remotely controlled.

[0049] The present invention can also be configured so that images captured by the vehicle-mounted camera 5d and the close-up camera 5e are displayed on goggles (not shown) worn by the operator. The displayed images can also be stereoscopic, and when the operator moves their head, the corresponding image is displayed on the goggles. Displaying a stereoscopic image on the goggles allows the operator to grasp a sense of distance. Furthermore, by displaying an image in the direction the operator is facing in real time, the operator can operate the felling vehicle 1 from a distance, feeling as if the work is being performed right in front of them. The present invention can also be configured so that an alarm is sounded to alert the operator operating the felling vehicle 1 when another operator or other person enters the field of view of the vehicle-mounted camera 5d or the close-up camera 5e.

[0050] 2, the rotating frame 6 is a member that is arranged between the traveling devices 4 (between the vertical members 2a) and is formed in a generally U-shape when viewed from above, and is provided with a recess 6a that receives a standing tree to be felled from the front side of the felling vehicle 1. This rotating frame 6 is attached to the vehicle body 2 so as to be rotatable about a rotation axis 6b that extends horizontally in the width direction of the vehicle body 2. In other words, the generally U-shaped rotating frame 6 is rotatably supported by support shafts 6c at the front ends of the legs on both sides relative to the vehicle body 2.

[0051] 4, a link mechanism 16 consisting of three links 16a, 16b, and 16c, and a tilt hydraulic cylinder 18 connected to the link mechanism 16 are connected to the rotating frame 6. The link mechanism 16 and the tilt hydraulic cylinder 18 are provided on both sides of the rotating frame 6, respectively, and by extending and contracting the tilt hydraulic cylinder 18 using hydraulic pressure generated by the engine 15, the rotating frame 6 can be rotated about the rotation axis 6b.

[0052] Specifically, the link 16a constituting the link mechanism 16 is rotatably attached to the support shaft 6c of the rotating frame 6 and fixed to the rotating frame 6. The link 16b is rotatably attached to the front end of the vertical member 2a of the vehicle body 2, rearward of the link 16a. The link 16c is rotatably attached to the links 16a and 16b so as to connect the tips of the links 16a and 16b. The tilt hydraulic cylinder 18 extends in the front-to-rear direction so as to connect the rear end of the link 16c to the horizontal member 2b of the vehicle body 2. As a result, when the tilt hydraulic cylinder 18 is extended or retracted, the link 16a rotates about the support shaft 6c, and the rotating frame 6 rotates together with the link 16a. As a result, the rotating frame 6 can be rotated forward via the link mechanism 16 from the standard state of the felling vehicle 1 shown in FIG. 1 .

[0053] In this embodiment, the rotating frame 6 is oriented substantially horizontally in the reference state of the felling vehicle 1 shown in FIG. 1 , and can be rotated forward by 165 degrees from this state. The maximum diameter of the root circumference of a tree that can be felled by the felling vehicle 1 of this embodiment is approximately 50 cm. As will be described later, even when a tree of this maximum diameter is received in the recess 6 a of the rotating frame 6 and held by the grapple device 8, the rotation axis 6 b of the rotating frame 6 is located further forward of the vehicle body 2 than the tree. After the tree held by the grapple device 8 is cut with the chainsaw 12, the rotating frame 6 can be rotated forward about the rotation axis 6 b, thereby felling the cut tree toward the front of the vehicle body 2.

[0054] Next, the configuration of the grapple device will be described with new reference to Figures 5 to 8. Figure 5 is a front view showing an enlarged view of the grapple device and other components provided on the felling vehicle according to the first embodiment of the present invention. Figures 6 to 8 are enlarged top views showing the grapple device and other components provided on the felling vehicle according to the first embodiment of the present invention, with Figure 6 showing the grapple in an open state, Figure 7 showing the grapple device holding a standing tree, and Figure 8 showing the grapple in a folded state.

[0055] As shown in Figures 5 to 8, the grapple device 8 includes two grapples 8a, 8b that extend forward and are configured to be openable and closable. These grapples 8a, 8b are configured to laterally grasp and hold a tree T to be felled that is received in the recess 6a of the rotating frame 6. That is, each grapple 8a, 8b is rotatably attached to the grapple device main body 8c via a support shaft 8d. Furthermore, each grapple 8a, 8b is configured to have a generally arc-shaped configuration that curves inward in a plan view. By rotating the grapples 8a, 8b from the state shown in Figure 6 in a direction in which their tips approach each other, the tree T can be held as shown in Figure 7. When the grapple device 8 is not in use, the grapples 8a, 8b can be folded by rotating them to a position in which they overlap each other, as shown in Figure 8.

[0056] In the reference state of the felling vehicle 1 shown in Fig. 1, each support shaft 8d of the grapple device 8 is oriented substantially vertically, and each grapple 8a, 8b rotates in a horizontal plane around the support shaft 8d. Furthermore, as shown in Fig. 5, each grapple 8a, 8b is composed of two plate-like members. The two plate-like members constituting the grapple 8a shown on the left side of Fig. 5 are configured with a wide gap between them in the vertical direction, while the two plate-like members constituting the grapple 8b shown on the right side are configured with a narrow gap between them in the vertical direction. Due to this configuration, when the grapples 8a, 8b intersect with each other, the two plate-like members constituting the grapple 8b fit between the two plate-like members constituting the grapple 8a (Figs. 7 and 8).

[0057] Furthermore, as shown in Fig. 6, opening and closing hydraulic cylinders 20a, 20b are connected to the base ends of the grapples 8a, 8b. By extending and contracting these opening and closing hydraulic cylinders 20a, 20b, the grapples 8a, 8b can be rotated from the open state shown in Fig. 6 to a state in which they hold a standing tree (Fig. 7) and a folded state (Fig. 8).

[0058] That is, the opening / closing hydraulic cylinder 20a extends in the width direction of the grapple device 8 so as to connect the base end of the grapple 8a to the grapple device main body 8c. Furthermore, the opening / closing hydraulic cylinder 20b extends in the width direction of the grapple device 8 so as to connect the base end of the grapple 8b to the grapple device main body 8c. With this configuration, when the opening / closing hydraulic cylinders 20a, 20b are extended from the state shown in Fig. 6, the base ends of the grapples 8a, 8b are moved outward in the width direction, and the grapples 8a, 8b are rotated about the support shaft 8d (Fig. 6 → Fig. 7 → Fig. 8).

[0059] Furthermore, a synchronization link 8e is provided so as to extend in the width direction of the grapple device 8. This synchronization link 8e is configured to connect the front side of the support shaft 8d at the base end of the grapple 8a with the rear side of the support shaft 8d at the base end of the grapple 8b. By providing the synchronization link 8e, the grapples 8a and 8b rotate synchronously (the grapple 8a and the grapple 8b rotate by approximately the same angle) when opening and closing.

[0060] 6, anti-slip members 8f are provided on the inside of each of the grapples 8a, 8b and on the front side of the grapple device main body 8c. The tree T held by the grapple device 8 comes into contact with each of the anti-slip members 8f, which prevents the tree T from slipping relative to each of the grapples 8a, 8b. This makes it difficult for the cut tree T or the cut tree T being transported to slip relative to each of the grapples 8a, 8b.

[0061] Next, as shown in Figure 4, the grapple device 8 is supported via a rotating arm 10 attached to the rotating frame 6. That is, the rotating arm 10 is rotatably attached to the rear end of the rotating frame 6, and extends substantially vertically upward when the tree-felling vehicle 1 is in the standard state shown in Figure 1. The grapple device main body 8c of the grapple device 8 is attached to the upper end of the rotating arm 10. Therefore, the rotating arm 10 supports the grapple device 8 above the rotating frame 6.

[0062] The rotating arm 10 is attached to the rotating frame 6 by a support shaft 10a that extends horizontally in the width direction of the felling vehicle 1, and the grapple device 8 attached to the rotating arm 10 can be directed in a desired direction by rotating the rotating arm 10 relative to the rotating frame 6. Specifically, a dump hydraulic cylinder 22 is provided to connect the rear end of the rotating frame 6 to the back side of the rotating arm 10, and by extending or contracting this dump hydraulic cylinder 22, the rotating arm 10 can be rotated relative to the rotating frame 6 around the support shaft 10a.

[0063] In the standard state of the felling vehicle 1 shown in Figure 1, the pivoting frame 6 and the pivoting arm 10 form a substantially right angle, and the pivoting arm 10 extends generally vertically upward. By retracting the dump hydraulic cylinder 22 from this state, the pivoting arm 10 is pivoted toward the rear of the felling vehicle 1. In this embodiment, the pivoting arm 10 can be pivoted rearward by approximately 45 degrees, and in this state, the angle between the pivoting frame 6 and the pivoting arm 10 in a side view is approximately 135 degrees (Figure 18).

[0064] Furthermore, a slide plate 10b is attached to the front side of the rotating arm 10, and the above-mentioned grapple device 8 is attached to this slide plate 10b. The slide plate 10b is configured to be slidable along the rotating arm 10. That is, the rotating arm 10 is provided with a guide mechanism (not shown) that guides the slide plate 10b, and this guide mechanism supports the slide plate 10b so that it can slide relative to the rotating arm 10.

[0065] Furthermore, a sliding hydraulic cylinder 24 is attached between the rotating arm 10 and the slide plate 10b, and by extending or contracting this sliding hydraulic cylinder 24, the slide plate 10b moves parallel to the rotating arm 10. That is, by extending the sliding hydraulic cylinder 24 from the standard state of the felling vehicle 1 shown in FIG. 1 , the slide plate 10b slides and the rotating arm 10 is extended. As a result, the grapple device 8 attached to the rotating arm 10 moves upward and away from the rotating frame 6. In this way, by rotating the rotating frame 6 and the rotating arm 10 and sliding the slide plate 10b, the grapple device 8 attached to the slide plate 10b can be positioned at various heights and angles relative to the vehicle body 2.

[0066] Next, referring to FIG. 9 , the flexible support mechanism that supports the grapple device 8 will be described. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 6 . First, as shown in FIG. 6 , the grapple device main body 8c of the grapple device 8 is attached to the slide plate 10b of the pivot arm 10 via a flexible support mechanism 26. This flexible support mechanism 26 allows the grapple device 8 to rotate about a predetermined axis relative to the pivot arm 10. That is, the flexible support mechanism 26 includes a roll rotation mechanism 28, an intermediate member 30, and a pitch rotation mechanism 32. Specifically, this flexible support mechanism 26 allows the grapple device main body 8c to rotate about a roll axis 28a and a pitch axis 32a relative to the slide plate 10b. By allowing the grapple device 8 to rotate in this manner, the grapple device 8 can be oriented to fit the tree to be felled, thereby enabling the tree to be securely held.

[0067] The roll rotation mechanism 28 is configured to connect the slide plate 10b and the intermediate member 30 of the universal support mechanism 26 so that they can rotate about a roll axis 28a. The roll axis 28a is oriented substantially horizontally in the fore-and-aft direction of the felling vehicle 1 when the felling vehicle 1 is in the standard state shown in Figure 1.

[0068] As shown in Figure 9, the roll rotating mechanism 28 has an inner race 28b fixed to the slide plate 10b (Figure 6), an outer race 28c fixed to the intermediate member 30, and a plurality of ball bearings 28d arranged between the inner race 28b and the outer race 28c. A substantially square opening 28e is provided in the center of the inner race 28b, and a rectangular shaft 28f with a substantially square cross section is received inside this opening 28e at an angle of approximately 45 degrees. This rectangular shaft 28f is fixed to the intermediate member 30, and its center coincides with the roll axis 28a.

[0069] Furthermore, elastically deformable roll dampers 28g are respectively disposed between the four corners of the opening 28e and each side of the rectangular shaft 28f. With this structure, when the intermediate member 30 rotates about the roll axis 28a relative to the slide plate 10b, the roll dampers 28g disposed at the four corners of the opening 28e are compressively deformed by the rectangular shaft 28f. In other words, the roll dampers 28g bias the intermediate member 30 so that the intermediate member 30 faces in a predetermined direction relative to the slide plate 10b.

[0070] In the standard state shown in FIG. 1 , the grapple device 8 is oriented so that the grapples 8 a, 8 b are positioned in a horizontal plane, and the roll damper 28 g biases the intermediate member 30 so that the grapple device 8 faces in this direction. When a rotational force in the roll direction acts on the grapple device 8, the roll damper 28 g is elastically deformed, allowing the grapple device 8 to rotate in the roll direction. When the applied rotational force is removed, the restoring force of the roll damper 28 g returns the grapple device 8 to its original orientation. In this manner, the roll rotation mechanism 28 of the universal support mechanism 26 elastically supports the grapple device 8 so as to allow the grapple device 8 to rotate about the roll axis relative to the rotating arm 10. In this embodiment, the roll rotation mechanism 28 allows the grapple device 8 to rotate left and right by approximately ±30 degrees.

[0071] 4 and 6, the pitch rotation mechanism 32 is configured to connect the intermediate member 30 of the universal support mechanism 26 and the grapple device main body 8c of the grapple device 8 so that they can rotate about a pitch axis 32a (FIG. 6). The pitch axis 32a is a rotation axis that is oriented approximately horizontally in the width direction of the felling vehicle 1 when the felling vehicle 1 is in the standard state shown in FIG. 1, and supports the grapple device main body 8c so that it can rotate in the pitch direction relative to the intermediate member 30.

[0072] The pitch rotation mechanism 32 includes a support shaft 32b that rotatably supports the grapple device main body 8c relative to the intermediate member 30, and a plurality of pitch dampers 32c arranged above and below the support shaft 32b. As shown in FIG. 4, the pitch dampers 32c are elastically deformable members, and four are attached to each of the intermediate member 30 and the grapple device main body 8c (only four are shown in FIG. 4). That is, the two pitch dampers 32c attached to the intermediate member 30 above the support shaft 32b abut against the two pitch dampers 32c attached to the grapple device main body 8c so as to face them. Similarly, the two pitch dampers 32c attached to the intermediate member 30 below the support shaft 32b abut against the two pitch dampers 32c attached to the grapple device main body 8c so as to face them.

[0073] These pitch dampers 32c bias the grapple device main body 8c so that the grapple device main body 8c faces a predetermined direction relative to the intermediate member 30. That is, in the standard state shown in FIG. 1 , the grapple device 8 is oriented so that the grapples 8a and 8b are positioned in a horizontal plane, and the pitch dampers 32c bias the grapple device main body 8c so that the grapple device 8 faces in this direction. With this structure, when a rotational force in the pitch direction acts on the grapple device 8, the pitch dampers 32c elastically deform, allowing the grapple device 8 to rotate about the pitch axis 32a. Furthermore, when the applied rotational force is removed, the restoring force of the pitch dampers 32c returns the grapple device 8 to its original direction. In this way, the pitch rotation mechanism 32 of the universal support mechanism 26 elastically supports the grapple device 8 so as to allow the grapple device 8 to rotate about the pitch axis relative to the rotating arm 10. In this embodiment, the grapple device 8 is allowed to rotate upward by approximately 15 degrees and downward by approximately 8 degrees from the reference state shown in FIG.

[0074] Next, as shown in Figure 2, the chainsaw 12, which is the cutting device, is attached to the front end portion on one side of the rotating frame 6 and is configured to be rotatable within a substantially horizontal plane. That is, the chainsaw 12 is attached to be rotatable around a support shaft 12a, which is provided on the front end portion on one side of the rotating frame 6 and is oriented in a substantially vertical direction. When not in use, the chainsaw 12 is stored in the rotating frame 6, facing rearward of the support shaft 12a so as to extend in the fore-and-aft direction of the felling vehicle 1.

[0075] Furthermore, a cutting hydraulic cylinder 34 is provided substantially parallel to the chainsaw 12 in the stored state, and this cutting hydraulic cylinder 34 is attached so as to connect the base end of the chainsaw 12 to the rear of the rotating frame 6. By extending and retracting the cutting hydraulic cylinder 34, the chainsaw 12 can be rotated in a horizontal plane about the support shaft 12a. When cutting a tree with the chainsaw 12, the cutting hydraulic cylinder 34 is retracted and the chainsaw 12 is rotated approximately 90 degrees forward while the tree to be felled is held by the grapple device 8. That is, the chainsaw 12 is rotated approximately 90 degrees forward from the position shown by the solid lines in FIG. 2 to the position shown by the imaginary lines, and the held tree is cut.

[0076] The length of the chainsaw 12 is slightly longer than the width of the recess 6a of the rotating frame 6 that is open forward. This allows the chainsaw 12 to reliably cut standing trees that are received and held in the recess 6a of the rotating frame 6. In addition, in the standard state shown in Figure 1, the rotating frame 6 is positioned below the grapple device 8, so the chainsaw 12 cuts standing trees below the grapples 8a, 8b. Although the felling vehicle 1 of this embodiment is equipped with the chainsaw 12 as a cutting device, a cutter blade (not shown) for cutting can also be provided as a cutting device.

[0077] 3, the winches 14 are provided on the upper outer sides of the traveling devices 4 in the width direction, and each includes a drum 14a and a wire rope 14b wound around the drum 14a. Each drum 14a is provided with a handle for manually rotating the drum 14a.

[0078] Here, the drum 14a is disposed on the same center line as the drive sprocket 4c (FIG. 1) of the traveling device 4, and is driven to rotate by a traveling motor 4e (FIG. 2) that drives the drive sprocket 4c. The drum 14a is connected to the drive sprocket 4c via a clutch device 14c, and when the clutch device 14c is engaged, the drum 14a rotates together with the drive sprocket 4c. In other words, each drum 14a is configured to be rotatable about an axis that is oriented horizontally in the width direction of the felling vehicle 1, and can reel in and pay out the wire rope 14b wound around it. The drum 14a is driven by the traveling motor 4e that drives the drive sprocket 4c of the traveling device 4, and is therefore driven to rotate in synchronization with the traveling motor 4e.

[0079] When the felling vehicle 1 is to perform work in the downward direction on a steep slope, the clutch device 14c is disengaged and the wire rope 14b is let out from the winch 14 to the rear (above) of the felling vehicle 1, and the end of the wire rope 14b is secured to a tree or structure. In this state, the clutch device 14c is connected and the traveling device 4 is operated, allowing the vehicle to move safely up a steep slope.

[0080] Here, the drum 14a of the winch 14 is driven to rotate by the travel motor 4e in synchronization with the drive sprocket 4c of the traveling device 4, thereby preventing the wire rope 14b from becoming significantly slack or the front of the traveling device 4 from being lifted up due to the pull of the wire rope 14b. In other words, because the diameter of the drum 14a that winds up the wire rope 14b is approximately the same as the pitch circle diameter of the drive sprocket 4c, the wire rope 14b is wound up or paid out in synchronization with the travel of the felling vehicle 1. Note that although the diameter of the drum 14a that winds up the wire rope 14b varies depending on the amount of wire rope 14b wound around it, as long as this diameter deviates by approximately ±5% of the pitch circle diameter of the drive sprocket 4c, the wire rope 14b can be wound up or paid out in synchronization with the travel of the felling vehicle 1 without any substantial problems.

[0081] Although the tree felling vehicle 1 of this embodiment is equipped with a winch 14, the present invention can also be configured so that a tether system is used to assist the travel of the tree felling vehicle 1. That is, in a tether system, a winch is fixed to a structure or the like above the tree felling vehicle 1, and the tip of the wire rope that is let out from this winch is tied to the tree felling vehicle 1. In this state, the wire rope can be let out or reeled in from the winch in accordance with the travel of the tree felling vehicle 1, thereby assisting the travel of the tree felling vehicle 1.

[0082] Next, the engine 15, which serves as a prime mover, is configured to generate power to operate the travel motor 4e of the travel device 4, the tilt hydraulic cylinder 18, the opening / closing hydraulic cylinders 20a and 20b, the dump hydraulic cylinder 22, the sliding hydraulic cylinder 24, and the cutting hydraulic cylinder 34. Specifically, hydraulic pressure is generated by the engine 15, and this hydraulic pressure is directed to each hydraulic motor and each hydraulic cylinder via control valves (not shown). The supplied hydraulic pressure activates these motors and cylinders. Specifically, the opening and closing of each control valve (not shown) controls the supply and stop of hydraulic pressure to each hydraulic motor and each hydraulic cylinder. The supplied hydraulic pressure causes each hydraulic motor and each hydraulic cylinder to rotate or extend / retract. In this embodiment, the engine 15 is composed of two internal combustion engines. Therefore, even if one internal combustion engine stops, hydraulic pressure can still be generated, maintaining the minimum functions of the felling vehicle 1, such as travel by the travel device 4, and allowing for safe felling operations.

[0083] The engine 15 is supported on the upper rear portion of the vehicle body 2 via a pair of brackets 15a extending from the vehicle body 2. Support shafts 15b extending substantially horizontally in the width direction of the felling vehicle 1 are provided at the tips of the brackets 15a, respectively, and the engine 15 is supported rotatably about these support shafts 15b. In this embodiment, the engine 15 can be rotated approximately 20 degrees forward and approximately 25 degrees rearward from the position shown in FIG. 1 . This allows the engine 15 to be maintained in a nearly horizontal position even when the felling vehicle 1 travels on an inclined surface, preventing impairment of the engine 15's functionality. The felling vehicle 1 of this embodiment can maintain its functionality even when placed on a steep slope inclined approximately 45 degrees in the fore-aft direction.

[0084] Next, the operation of the felling vehicle 1 according to the first embodiment of the present invention will be described with reference to Figures 10 to 20. Figures 10 to 14 are diagrams showing the procedure for felling and transporting a standing tree on flat ground using the felling vehicle 1 of this embodiment. Figures 15 to 17 are diagrams showing the procedure for felling a standing tree on an uphill slope (when the front of the felling vehicle 1 is higher) using the felling vehicle 1 of this embodiment. Figures 18 to 20 are diagrams showing the procedure for felling a standing tree on a downhill slope (when the front of the felling vehicle 1 is lower) using the felling vehicle 1 of this embodiment.

[0085] The felling vehicle 1 of this embodiment is equipped with a transceiver (not shown), and each hydraulic motor and each hydraulic cylinder are operated based on control signals received by this transceiver. Therefore, the worker performing the felling operation can safely perform the work described below by using a controller (not shown) at hand to send instructions to the transceiver (not shown) of the felling vehicle 1 from a safe location. The transceiver (not shown) is also equipped with a GPS (Global Positioning System), making it easy to identify the location where the tree has been felled. Furthermore, the present invention can be configured so that the route to the felling site is stored and the felling vehicle 1 automatically travels along that route to return.

[0086] First, when felling a tree on flat ground, as shown in Figure 10, the felling vehicle 1 is driven to a position where the tree T to be felled can be received in the recess 6a of the rotating frame 6. At this time, it is preferable that the rotating frame 6 and the rotating arm 10 are in the basic position shown in Figure 1. Next, with the tree T to be felled received in the recess 6a, the opening and closing hydraulic cylinders 20a, 20b (Figure 6) are operated, and the grapples 8a, 8b of the grapple device 8 hold the tree T. Although trees generally do not extend completely perpendicular to the ground, the grapple device 8 is elastically supported by the universal support mechanism 26 on the rotating arm 10, so that the grapple device 8 is automatically oriented in the appropriate direction.

[0087] In this state, the chainsaw 12 is operated and the cutting hydraulic cylinder 34 (Fig. 2) is retracted, thereby rotating the chainsaw 12 forward from the position shown by the solid line in Fig. 2 to the position shown by the imaginary line in Fig. 2. As a result, the tree T is cut almost horizontally, approximately parallel to the rotating frame 6.

[0088] 11 , while the grapple device 8 is holding the cut tree T, the tilt hydraulic cylinder 18 is operated to rotate the rotating frame 6 forward, thereby toppling the cut tree toward the front of the vehicle body 2. Here, the rotating frame 6 is rotated about its rotation axis 6b ( FIG. 2 ), and the rotation axis 6b is positioned forward of the cut tree T. As a result, the cut tree T is lifted upward from the stump and topples forward.

[0089] As a result, when the cut tree T falls, the cut tree T does not substantially come into contact with the stump, and no reaction force is applied to the felling vehicle 1 due to contact between the cut tree T and the stump. This allows the cut and falling tree T to be easily controlled by rotating the rotating frame 6, allowing the worker to fell the tree T in the direction intended, thereby safely carrying out the felling work. Furthermore, the cut tree T will fall forward due to its own weight, but at this time, the tilt hydraulic cylinder 18 applies a torque to the rotating frame 6 in the opposite direction to the falling direction of the tree T, thereby slowing the falling speed of the tree T. Specifically, hydraulic pressure is supplied to the tilt hydraulic cylinder 18 via a counterbalance valve (not shown), preventing the tilt hydraulic cylinder 18 from suddenly extending when the tree T falls. That is, the tilt hydraulic cylinder 18 is slowly extended so as to resist the tree T from falling, and a torque in the opposite direction to the falling direction of the tree T is applied to the rotating frame 6, resulting in a gentle fall of the tree T. Therefore, the tilt hydraulic cylinder 18 functions as a torque application device for the rotating frame 6. This makes it possible to prevent the occurrence of an accident in which the vehicle overturns or damage to the device due to a reaction force acting on the felling vehicle 1 during felling.

[0090] After the tree has been cut, as shown in FIG. 12, the rotating frame 6 is rotated until the cut tree T is approximately parallel to the ground. In this state, the felling vehicle 1 is driven backward to transport the cut tree T. At this time, as shown in FIG. 13, the sliding hydraulic cylinder 24 is extended, causing the slide plate 10b to slide relative to the rotating arm 10 in the extending direction. This moves the base of the cut tree T forward of the felling vehicle 1. As a result, as shown in FIG. 14, even when the felling vehicle 1 turns while transporting the cut tree T, there is little interference between the base of the tree T and the front of the felling vehicle 1, allowing the felling vehicle 1 to turn relatively freely. The grapple device 8 is supported on the rotating arm 10 via a flexible support mechanism 26. Therefore, when the felling vehicle 1 transporting a standing tree T travels around a curve, the standing tree T is allowed to rotate around the roll axis 28a relative to the pivoting arm 10, allowing the standing tree T to be transported smoothly.

[0091] In the felling vehicle 1 of this embodiment, the diameter of felled trees is automatically measured and the number of felled trees is automatically counted. This data is associated with the tree species input by the worker via a controller (not shown) before the felling operation and stored in a control device (not shown) built into the felling vehicle 1. The data stored in the control device in this way can be retrieved after the operation and used to record the felling operation and for tallying up the data.

[0092] Next, the procedure for felling a tree on an uphill slope (when the front of the felling vehicle 1 is higher) will be described with reference to Figures 15 to 17. First, when the felling vehicle 1 is traveling uphill, it is preferable to run it with the rotating frame 6 rotated approximately 90 degrees from the standard state shown in Figure 1, as shown in Figure 15.

[0093] Next, when the tree felling vehicle 1 approaches the tree to be felled, the rotating frame 6 is rotated to a direction substantially perpendicular to the tree T, as shown in Figure 16. In the example shown in Figure 16, the tree T extends vertically, so the rotating frame 6 is oriented substantially horizontally. The tree felling vehicle 1 is then driven to a position where the tree T to be felled can be received in the recess 6a of the rotating frame 6. Next, with the tree to be felled received in the recess 6a, the grapple device 8 holds the tree T. At this time, the grapple device 8 is automatically oriented in the appropriate direction by the universal support mechanism 26.

[0094] In this state, the chainsaw 12 is operated and rotated forward, cutting the tree substantially parallel to the rotating frame 6. In the example shown in FIG. 16 , the tree T extends substantially vertically, and the rotating frame 6 is oriented substantially horizontally, so the tree T is cut horizontally. Next, as shown in FIG. 17 , the cut tree T is held by the grapple device 8, and the rotating frame 6 is rotated forward, causing the cut tree T to fall forward of the vehicle body 2. In this case, too, the rotating frame 6 is rotated about the rotation axis 6 b, and the cut tree T is lifted upward from the stump and falls forward. The operation of transporting the cut tree T is similar to that when felling a tree T on flat ground, and therefore a description thereof will be omitted. Here, in felling operations on an uphill slope, the tree is cut substantially horizontally. Therefore, after transporting the standing tree T, the stumps that remain after being cut horizontally can be cut in a direction approximately parallel to the slope using a chainsaw 12 so that no tall stumps remain in the forest area.

[0095] Next, the procedure for felling a tree on a downward slope (when the front of the felling vehicle 1 is lower) will be described with reference to Figures 18 to 20. First, when the felling vehicle 1 approaches the tree to be felled, as shown in Figure 18, the dump hydraulic cylinder 22 is actuated to rotate the rotating arm 10 relative to the rotating frame 6 so that the rotating arm 10 is approximately parallel to the tree to be felled. At this time, if necessary, the tilt hydraulic cylinder 18 may be actuated to also rotate the rotating frame 6 so that the rotating arm 10 is approximately parallel to the tree.

[0096] 18, the tree extends vertically, so the rotating arm 10 is oriented substantially vertically. The tree felling vehicle 1 is then driven to a position where the tree to be felled can be received in the recess 6a of the rotating frame 6. Next, with the tree received in the recess 6a, the grapple device 8 holds the tree. At this time, the grapple device 8 is automatically oriented appropriately by the universal support mechanism 26.

[0097] Furthermore, when the slope is steep, as shown in Figure 19, the wire rope 14b is reeled out rearward from each winch 14 and the tip of each wire rope 14b is fixed to a tree or the like located above the felling vehicle 1. Then, in synchronization with the movement of the felling vehicle 1, the wire rope 14b is reeled out from the drum 14a of each winch 14 while the felling vehicle 1 is moved forward. This allows the felling vehicle 1 to travel safely and stably even on steep slopes.

[0098] With the tree T held by the grapple device 8, the chainsaw 12 is operated and rotated forward, cutting the tree T approximately parallel to the rotating frame 6. In the example shown in FIG. 18 , the tree T extends approximately vertically, and the rotating frame 6 is oriented approximately parallel to the slope, so the tree T is cut approximately parallel to the slope. Next, as shown in FIG. 20 , the cut tree 20 is held by the grapple device 8, and the rotating frame 6 is rotated forward, causing the cut tree to fall forward of the vehicle body 2. In this case, too, the rotating frame 6 is rotated about the rotation axis 6 b, and the cut tree is lifted upward from the stump and falls forward. The operation of transporting the cut tree is similar to that when felling trees on flat ground, and therefore a description thereof will be omitted.

[0099] In the felling work vehicle 1 of the first embodiment of the present invention, the rotation axis 6b (FIG. 2) about which the rotating frame 6 rotates when felling a tree T is located further forward of the vehicle body 2 than the tree T held by the grapple device 8. Therefore, the cut tree T is lifted upward from the stump by the rotation of the rotating frame 6, and the tree T held by the grapple device 8 falls reliably with the rotation axis 6b of the rotating frame 6 as a fulcrum. As a result, the direction in which the cut tree T falls is stable, allowing for safe felling work.

[0100] Furthermore, according to the felling work vehicle 1 of this embodiment, the grapple device 8 is supported by a pivoting arm 10 that can rotate around an axis extending in the width direction of the vehicle body 2, so that the grapples 8a, 8b of the grapple device 8 can be applied at approximately right angles to standing trees T growing on slopes (Figure 18), and the standing trees T can be securely held by the grapple device 8.

[0101] Furthermore, according to the felling work vehicle 1 of this embodiment, the flexible support mechanism 26 (Figures 4, 6, and 9) allows the grapple device 8 to rotate relative to the pivoting arm 10, so that the orientation of the grapple device 8 can be easily adapted to the direction of the standing tree T to be held, and the standing tree T can be securely held.

[0102] Furthermore, according to the felling work vehicle 1 of this embodiment, the universal support mechanism 26 elastically supports the grapple device 8 to allow the grapple device 8 to rotate (FIGS. 4 and 9), so an elastic force acts on the grapple device 8 to return it to its original direction. As a result, after the tree T held by the grapple device 8 is cut, the grapple device 8 returns to its original direction due to the elastic force, making it possible to stabilize the direction of the tree T being held.

[0103] Furthermore, with the felling vehicle 1 of this embodiment, the rotating arm 10 is configured to be extendable (FIGS. 4 and 13), and the grapple device 8 is separated from the rotating frame 6, so that when the felled tree T is transported (FIG. 14), the base of the felled tree T is farther away from the front of the felling vehicle 1. As a result, when the felling vehicle 1 transporting the tree T turns, the front of the felling vehicle 1 is less likely to interfere with the base of the tree T, making transport easier.

[0104] Furthermore, with the felling vehicle 1 of this embodiment, the chainsaw 12, which is the cutting device, cuts the tree T to be felled below the pivot axis 6b (FIG. 4), so even if the tree T is thick, when felling the tree, the cut tree T is reliably lifted upward from the stump, reliably preventing the cut tree T from coming into contact with the stump. This makes it possible to more steadily fell the tree T.

[0105] Furthermore, according to the felling work vehicle 1 of this embodiment, the tilt hydraulic cylinder 18, which is a torque-adding device, reduces the speed at which the standing tree T falls, so that the cut standing tree T can be felled slowly, and the occurrence of vehicle tipping accidents or damage to the device due to the reaction force acting on the felling work vehicle 1 during felling can be prevented.

[0106] Furthermore, according to the felling vehicle 1 of this embodiment, the drum 14a of the winch 14 pays out or winds up the wire rope 14b in synchronization with the traveling device 4, so that when the felling vehicle 1 travels with the assistance of the winch 14, it is possible to prevent the wire rope 14b from becoming too slack or one end of the felling vehicle 1 from being pulled up by the wire rope 14b, allowing the felling vehicle 1 to travel stably.

[0107] Furthermore, according to the felling work vehicle 1 of this embodiment, the engine 15, which is the prime mover, is supported on the vehicle body 2 so that it can rotate about an approximately horizontal axis. Therefore, even when the felling work vehicle 1 is used to perform felling work on slopes, the engine 15 can be maintained in a nearly horizontal position, and the engine 15 can be operated reliably.

[0108] Furthermore, according to the felling work vehicle 1 of this embodiment, the cutting device is a chainsaw 12, so that tree species that cannot be cut with a cutter blade can be cut, and the cutting device can be made lighter.

[0109] Next, a felling vehicle according to a second embodiment of the present invention will be described with reference to Figures 21 to 28. The felling vehicle of this embodiment differs from the first embodiment described above in the connection structure of the pivoting arm to the pivoting frame and the direction of movement. Therefore, the following will only describe the differences between the second embodiment of the present invention and the first embodiment, and will omit a description of the same configurations, operations, and effects.

[0110] Figure 21 is a side view of a felling vehicle according to a second embodiment of the present invention, showing the range in which the pivoting frame can be rotated. Figure 22 is a side view of a felling vehicle according to a second embodiment of the present invention, showing the range in which the pivoting arm can be rotated in the pitch direction. Figure 23 is a front view of a felling vehicle according to a second embodiment of the present invention, showing the range in which the pivoting arm can be rotated in the roll direction.

[0111] As shown in Figure 21, a felling vehicle 101 according to the second embodiment of the present invention comprises a vehicle body 102, a pair of traveling devices 104 provided on both sides of the vehicle body 102 in the width direction, and a rotating frame 106 disposed between the traveling devices 104. Furthermore, a grapple device 108 that holds the tree to be felled is connected to the rotating frame 106 via a rotating arm 110. A camera 105 that captures images of the situation in front of the felling vehicle 101 is attached to the upper surface of the grapple device 108. In addition, a chainsaw 112, which serves as a cutting device, is attached to the rotating frame 106. The configurations of the vehicle body 102 and the traveling devices 104 are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0112] Furthermore, similarly to the first embodiment, the rotating frame 106 attached to the vehicle body 102 is rotatable about a rotation axis 106b. In this embodiment, the rotating frame 106 is also a member formed in a generally U-shape when viewed from above, and is configured to be rotatable forward about a rotation axis 106b oriented in the width direction of the vehicle body 102 within a horizontal plane. That is, as shown in FIG. 21 , the rotating frame 106 is configured to be rotatable forward within a range of approximately 160 degrees from a reference state indicated by a solid line oriented in a generally horizontal direction to a position indicated by a dashed line. Thus, the configurations of the link mechanism 116 and the tilt hydraulic cylinder 118 for tilting (rotating) the rotating frame 106 forward are also similar to those of the first embodiment, and therefore will not be described here.

[0113] Next, as shown in Figure 22, the rotating arm 110 is attached to the rotating frame 106 so as to be rotatable in the front-to-rear direction about a lateral support shaft 110a. The lateral support shaft 110a is an axis oriented in the width direction of the vehicle body 102 within a horizontal plane, and the rotating arm 110 can rotate about the lateral support shaft 110a relative to the rotating frame 106. That is, in the reference state shown by the solid line in Figure 21, the rotating arm 110 is oriented in a substantially vertical direction, at a substantially right angle to the rotating frame 106. In this embodiment, as shown in Figure 22, the rotating arm 110 can rotate approximately 30 degrees forward and approximately 40 degrees backward from the reference state shown in Figure 21. Thus, when the pivot arm 110 is rotated forward by approximately 30 degrees, the angle between the pivot frame 106 and the pivot arm 110 is approximately 60 degrees, and when the pivot arm 110 is rotated backward by approximately 40 degrees, the angle is approximately 130 degrees.

[0114] Similar to the first embodiment, the slide plate 110b is attached to the front side of the rotating arm 110, and the grapple device 108 is attached to the slide plate 110b via a roll rotation mechanism 128 and a pitch rotation mechanism 132. Therefore, in this embodiment, the rotating arm 110 is also configured to be extendable, and the grapple device 108 attached to the slide plate 110b can be moved up and down from a reference state. Furthermore, the grapple device 108 is elastically supported by the roll rotation mechanism 128 and the pitch rotation mechanism 132 relative to the slide plate 110b, and is allowed to roll and pitch within a predetermined range relative to the rotating arm 110.

[0115] 23 , the rotating arm 110 is attached to the rotating frame 106 so as to be rotatable in the left-right direction around a vertical support shaft 111a. The vertical support shaft 111a is an axis oriented in the front-rear direction of the vehicle body 102 within a horizontal plane, and the rotating arm 110 can rotate about the vertical support shaft 111a relative to the rotating frame 106. That is, the vertical support shaft 111a is provided along an axis extending in the front-rear direction of the vehicle body 102, and the rotating arm 110 can rotate about the axis extending in the front-rear direction of the vehicle body 102. As a result, the rotating arm 110 can rotate about the vertical support shaft 111a in the left-right direction by approximately 10 degrees from a reference state shown by a solid line in FIG. 23 to a position shown by a dashed line. In addition, in this embodiment, the vertical support shaft 111a is arranged so as to intersect with the above-mentioned horizontal support shaft 110a at one point, and the rotating arm 110 can rotate in the front-to-back and left-to-right directions around this intersection point.

[0116] Next, the connection structure between the rotating frame and the rotating arm will be described with additional reference to Figures 24 and 25. Figure 24 is an enlarged side view showing the connection portion between the rotating frame and the rotating arm. Figure 25A is a side view of the swing pin that connects the rotating frame and the rotating arm, Figure 25B is a top view of the swing pin, and Figure 25C is a front view of the swing pin.

[0117] As shown in Figure 24, the rotating frame 106 and the rotating arm 110 are connected via a swing pin 111. As shown in Figure 25B, the swing pin 111 is a member that is approximately T-shaped when viewed from above, and is a member in which a cylindrical vertical support shaft 111a extending in the front-to-rear direction of the felling vehicle 101 and a cylindrical bearing portion 111b extending in the width direction of the felling vehicle 101 are integrated into a substantially T-shape. By connecting the rotating arm 110 to the rotating frame 106 via the swing pin 111, the rotating arm 110 is allowed to rotate in the front-to-rear and left-to-right directions around the intersection P of the central axis A1 of the vertical support shaft 111a and the central axis A2 of the bearing portion 111b.

[0118] The bearing portion 111b of the swing pin 111 is attached in a horizontal plane facing in the width direction of the felling vehicle 101, and rotatably receives a lateral support shaft 110a, which is a shaft fixed to the rotating arm 110. As a result, the rotating arm 110 is connected to the swing pin 111 so as to be rotatable in the front-to-rear direction around the lateral support shaft 110a (central axis A2).

[0119] Meanwhile, the vertical support shaft 111a of the swing pin 111 is rotatably received in a bearing member 106c fixed to the rotating frame 106. The bearing member 106c is a cylindrical member that is fixed to the center of the width direction of the rotating frame 106, facing the front-to-rear direction in a horizontal plane. The inner peripheral surface of the bearing member 106c functions as a bearing that receives the vertical support shaft 111a of the swing pin 111. As a result, the swing pin 111 is connected to the rotating frame 106 so as to be rotatable in the left-right direction around the vertical support shaft 111a (central axis A1).

[0120] 25C, two female screw holes 111c are provided at the tip of the vertical support shaft 111a. Then, as shown in Fig. 24, a retaining plate 114, which is a circular plate, is fixed to the tip of the vertical support shaft 111a with two bolts 114a (only one is shown in Fig. 24). That is, with the vertical support shaft 111a of the swing pin 111 inserted into the bearing member 106c, the retaining plate 114 is fixed to each of the female screw holes 111c with the two bolts 114a, thereby preventing the vertical support shaft 111a from coming off the bearing member 106c.

[0121] In this way, by connecting the rotating frame 106 and the rotating arm 110 via the swing pin 111, the rotating arm 110 is allowed to rotate in the front-rear direction and the left-right direction relative to the rotating frame 106. That is, the horizontal support shaft 110a of the rotating arm 110 rotates in the bearing portion 111b of the swing pin 111, allowing the rotating arm 110 to rotate in the front-rear direction relative to the rotating frame 106 as shown in Fig. 22. Furthermore, the vertical support shaft 111a of the swing pin 111 rotates in the bearing member 106c fixed to the rotating frame 106, allowing the rotating arm 110 to rotate in the left-right direction relative to the rotating frame 106 as shown in Fig. 23.

[0122] 22 and 23, a dump swing hydraulic cylinder 122 is provided on each of the left and right sides of the swing pin 111 (only one is shown in FIG. 22). As shown in FIG. 22, these dump swing hydraulic cylinders 122 are provided to connect the rear end of the rotating frame 106 to the back side of the rotating arm 110. By synchronously shortening these dump swing hydraulic cylinders 122 (shortening both dump swing hydraulic cylinders 122 to the same length), the rotating arm 110 is dumped (rotated) rearward relative to the rotating frame 106, as shown by the dashed line in FIG. 22. By synchronously extending the dump swing hydraulic cylinders 122, the rotating arm 110 is dumped (rotated) forward relative to the rotating frame 106, as shown by the dashed line in FIG. 22.

[0123] On the other hand, as shown in Figure 23, the rotating arm 110 can be swung left and right by extending one dump swing hydraulic cylinder 122 and retracting the other dump swing hydraulic cylinder 122. That is, in Figure 23, by retracting the right dump swing hydraulic cylinder 122 and extending the left dump swing hydraulic cylinder 122, the rotating arm 110 rotates to the right about the vertical support shaft 111a relative to the rotating frame 106. On the other hand, by extending the right dump swing hydraulic cylinder 122 and retracting the left dump swing hydraulic cylinder 122, the rotating arm 110 rotates to the left about the vertical support shaft 111a. In this way, in the felling work vehicle 101 of this embodiment, by extending or retracting each of the two dump swing hydraulic cylinders 122, the rotating arm 110 can be dumped in the front-rear direction relative to the rotating frame 106 (Figure 22) and can also be swung left and right (Figure 23).

[0124] Next, the operation of the felling vehicle 101 according to the second embodiment of the present invention will be described with reference to Figures 26 to 28. Figure 26 is a diagram showing the felling vehicle of this embodiment felling a standing tree on a slope with a lateral gradient. Figure 27 is a diagram showing the felling vehicle of this embodiment felling a standing tree on a downward slope. Figure 28 is a diagram showing the felling vehicle of this embodiment felling a standing tree on an upward slope.

[0125] First, as shown in FIG. 26 , when felling a tree on a slope with a lateral gradient (a slope where the right and left sides of the felling vehicle 101 are at different heights), the rotating arm 110 is swung in the roll direction. That is, by extending one of the two dump swing hydraulic cylinders 122 and retracting the other, the rotating arm 110 is rotated in the roll direction relative to the rotating frame 106 about the vertical support shaft 111 a. This allows the rotating arm 110 to be approximately parallel to a tree T growing vertically on a slope with a lateral gradient. In this state, the rotating arm 110 is oriented approximately vertically. Meanwhile, the rotating frame 106 is maintained in the reference state shown in FIG. 21 , and the rotating frame 106 and the slope are oriented approximately parallel.

[0126] Next, the felling work vehicle 101 is driven to a position where the tree T can be received in the recess 106a of the rotating frame 106. Furthermore, with the tree T received in the recess 106a, the grapple of the grapple device 108 is rotated, and the tree T is held by the grapple device 108. Here, by rotating the rotating arm 110 in the roll direction, the rotating arm 110 is oriented approximately parallel to the tree T, so that the grapple of the grapple device 108 can be brought into contact with the tree T at an approximately right angle, and the tree T can be firmly held. Next, with the tree T held, the chainsaw 112 provided on the rotating frame 106 is operated, and the tree T is cut below the grapple device 108. Here, the chainsaw 112 is rotated in a plane approximately parallel to the rotating frame 106 to cut the tree T, so that the tree T is cut on a plane approximately parallel to the slope.

[0127] After cutting the tree T, the tilt hydraulic cylinder 118 ( FIG. 21 ) is extended while the tree T is held by the grapple device 108, thereby tilting (rotating) the rotating frame 106 forward about the rotation axis 106b. This allows the tree T to be felled toward the front of the felling vehicle 101. After felling the tree T, the felling vehicle 101 is driven to transport the tree T while holding it with the grapple device 108, similar to the first embodiment described above. As described above, with the felling vehicle 101 of this embodiment, the rotating arm 110 can be rotated in the roll direction relative to the rotating frame 106, so that even trees T growing on slopes with a lateral gradient can be held and felled by the grapple device 108. This eliminates the need to adjust the direction of the felling vehicle 101 to match the inclination of the slope, allowing for smooth felling operations.

[0128] Next, as shown in Figure 27, when felling a tree on a downward slope (a slope where the front side of the felling vehicle 101 is lower), the rotating arm 110 is dumped (rotated) rearward. That is, by shortening the two dump swing hydraulic cylinders 122 by the same length, the rotating arm 110 is rotated rearward in the pitch direction relative to the rotating frame 106 around the lateral support shaft 110a. This allows the rotating arm 110 to be approximately parallel to a tree T growing vertically on a downward slope. In this state, the rotating arm 110 is oriented approximately vertically, while the rotating frame 106 is oriented approximately parallel to the slope.

[0129] Next, the felling work vehicle 101 is driven to a position where the tree T can be received in the recess 106a of the rotating frame 106. Furthermore, the tree T is held by the grapple device 108, and in this state, the chainsaw 112 is operated to cut the tree T below the grapple device 108. Here, the chainsaw 112 is rotated in a plane approximately parallel to the rotating frame 106 to cut the tree T, so that the tree T is cut on a plane approximately parallel to the slope.

[0130] After cutting, the tilt hydraulic cylinder 118 is extended while holding the tree T, thereby tilting (rotating) the rotating frame 106 forward about the rotation axis 106b. This allows the tree T to be felled toward the front of the tree-felling vehicle 101. After the tree T has been felled, it is transported in the same manner as in the first embodiment described above. As described above, with the tree-felling vehicle 101 of this embodiment, the rotating arm 110 can be dumped rearward relative to the rotating frame 106, so that a tree T growing on a downward slope can be held by the grapple device 108 while maintaining the rotating frame 106 parallel to the slope. As a result, the tree T can be cut and felled on a plane parallel to the slope. Therefore, even if the tree T is growing on a downward slope, it can be cut at a low position on a plane parallel to the slope, and the stump remaining after cutting is less likely to interfere with subsequent tree-felling operations.

[0131] Next, as shown in Figure 28, when felling a tree on an uphill slope (a slope where the front side of the felling vehicle 101 is higher), the rotating arm 110 is dumped (rotated) forward. That is, by extending the two dump swing hydraulic cylinders 122 by the same length, the rotating arm 110 is rotated forward in the pitch direction relative to the rotating frame 106 about the lateral support shaft 110a. This allows the rotating arm 110 to be made substantially parallel to a tree T growing vertically on an uphill slope without rotating the rotating frame 106 (while maintaining the rotating frame 106 in the reference state shown in Figure 21). In this state, the rotating arm 110 is oriented substantially vertically, while the rotating frame 106 is oriented substantially parallel to the slope.

[0132] Next, the felling work vehicle 101 is driven to a position where the tree T can be received in the recess 106a of the rotating frame 106. Furthermore, the tree T is held by the grapple device 108, and in this state, the chainsaw 112 is operated to cut the tree T below the grapple device 108. Here, the chainsaw 112 is rotated in a plane approximately parallel to the rotating frame 106 to cut the tree T, so that the tree T is cut on a plane approximately parallel to the slope.

[0133] After cutting, the tilt hydraulic cylinder 118 is extended while holding the tree T, thereby tilting (rotating) the rotating frame 106 forward about the rotation axis 106b. This allows the tree T to be felled toward the front of the tree-felling vehicle 101. After the tree T has been felled, it is transported in the same manner as in the first embodiment described above. As described above, with the tree-felling vehicle 101 of this embodiment, the rotating arm 110 can be dumped forward relative to the rotating frame 106, so that the grapple device 108 can hold a tree T growing on an uphill slope while maintaining the rotating frame 106 in its reference position. As a result, the tree T can be cut on a plane parallel to the slope. By cutting a tree T growing on an uphill slope at a low position on a plane parallel to the slope, the stump remaining after cutting is low and less likely to interfere with subsequent tree-felling operations.

[0134] Note that FIG. 27 illustrates felling of a tree T on a downward slope, and FIG. 28 illustrates felling of a tree T on an upward slope. Also, FIG. 26 illustrates felling of a tree T on a slope inclined left-right. However, the felling work vehicle 101 of this embodiment can also hold and cut a tree T growing on a general slope that is inclined both forward and backward (upward or downward) and left-right with the grapple device 108. In this case, the rotating arm 110 can be dumped (rotated) about the horizontal support shaft 110a relative to the rotating frame 106 and simultaneously swung (rotated) about the vertical support shaft 111a, thereby orienting the rotating arm 110 approximately parallel to the tree T. Therefore, the grapple device 108 can hold and cut the tree T without having to consider the direction of the slope on which the tree T grows (the direction in which the slope's inclination angle is greatest) and the direction of the vehicle body 102.

[0135] As described above, the work of felling a tree T includes the steps of adjusting the rotating arm 110 to the direction in which the tree T extends, moving the felling vehicle 101 to a position where it can hold the tree T, holding the tree T with the grapple device 108, cutting the held tree T with the cutting device, turning the rotating frame 106 to fall the cut tree T forward, and transporting the felled tree T. The present invention can also be configured so that the felling vehicle 101 is equipped with a controller (not shown) that can execute each of these steps, and so that some or all of the above steps are executed automatically. In this case, the present invention can be configured so that the controller executes each step based on images from the camera 105 installed on the felling vehicle 101.

[0136] According to the second embodiment of the felling work vehicle 101 of the present invention, the grapple device 108 is supported by a pivoting arm 110 that can rotate (Figure 23) around an axis (vertical support axis 111a) extending in the fore-and-aft direction of the vehicle body 102. Therefore, the grapple of the grapple device 108 can be applied at almost a right angle (Figure 26) to a standing tree T growing on a slope that inclines in the left-right direction of the vehicle body 102, and the standing tree T can be securely held by the grapple device 8.

[0137] Furthermore, with the felling work vehicle 101 of this embodiment, even when the tree T is growing on an upslope or downslope, the grapple device 108 is configured to be able to hold the tree T while maintaining the rotating frame 106 approximately parallel to the slope (FIGS. 27 and 28), so even when the tree T is growing on a slope, the tree T can be cut at a low position approximately parallel to the slope. As a result, the height of the stump after felling the tree T can be kept low, and after felling the tree T, the stump is less likely to get in the way when felling the next tree T, allowing the felling work to proceed smoothly.

[0138] Furthermore, according to the felling work vehicle 101 of this embodiment, even a standing tree T growing on a slope that inclines in the left-right direction of the vehicle body 102 can be held by the grapple device 108 (Figure 26), so felling work can be performed without aligning the fore-and-aft direction of the vehicle body 102 with the inclination direction of the slope, allowing the felling work to proceed smoothly.

[0139] Although the preferred embodiment of the present invention has been described above, various modifications can be made to the above-described embodiment. In particular, in the above-described embodiment, the rotating frame is directly attached to the vehicle body, but it may be attached to the vehicle body via another fixed or movable member.

[0140] REFERENCE SIGNS LIST 1 Felling work vehicle 2 Vehicle body 2a Vertical member 2b Horizontal member 2c Connecting member 2d Pole 4 Traveling device 4a Front driven wheel 4b Rear driven wheel 4c Drive sprocket 4d Crawler 4e Traveling motor 5a Light 5b Speaker 5c Safety light 5d Vehicle-side camera 5e Close-up camera 6 Rotating frame 6a Recess 6b Rotation axis 6c Support shaft 8 Grapple device 8a, 8b Grapple 8c Grapple device body 8d Support shaft 8e Synchronizing link 10 Rotating arm 10a Support shaft 10b Slide plate 12 Chainsaw (cutting device) 12a Support shaft 14 Winch 14a Drum 14b Wire rope 14c Clutch device 15 Engine (prime mover) 15a Bracket DESCRIPTION OF SYMBOLS 15b Support shaft 16 Link mechanism 16a, 16b, 16c Link 18 Tilt hydraulic cylinder (torque applying device) 20a, 20b Opening / closing hydraulic cylinder 22 Dump hydraulic cylinder 24 Sliding hydraulic cylinder 26 Free support mechanism 28 Roll rotation mechanism 28a Roll axis 28b Inner race 28c Outer race 28d Ball bearing 28e Opening 28f Rectangular shaft 28a Roll damper 30 Intermediate member 32 Pitch rotation mechanism 32a Pitch axis 32b Support shaft 32c Pitch damper 34 Cutting hydraulic cylinder 101 Felling work vehicle 102 Vehicle body 104 Traveling device 105 Camera 106 Rotating frame 106b Rotation axis 106c Bearing member 108 Grapple device 110 Rotating arm 110a Horizontal support shaft 110b Slide plate 111 Swing pin 111a Vertical support shaft 111b Bearing portion 111c Female thread hole 112 Chainsaw (cutting device) 116 Link mechanism 118 Tilt hydraulic cylinder 122 Dump swing hydraulic cylinder 128 Roll rotation mechanism 132 Pitch rotation mechanism

Claims

1. A felling work vehicle for felling standing trees, comprising: a vehicle body; a pair of traveling devices provided on both sides of the vehicle body in the width direction; a rotating frame arranged between the traveling devices and provided with a recess for receiving the tree to be felled from the front side; a grapple device connected to the rotating frame and equipped with a grapple for holding the tree to be felled received in the recess of the rotating frame by embracing it from the side; and a cutting device for cutting the tree held by the grapple device below the grapple, wherein the rotating frame is attached to the vehicle body so as to be rotatable around a rotation axis extending in the width direction of the vehicle body, and the rotation axis is positioned so as to be located further forward of the vehicle body than the standing tree held by the grapple device, and the felling work vehicle is characterized in that the rotation of the rotating frame lifts up the cut tree while felling it towards the front of the vehicle body.

2. A felling vehicle as described in claim 1, further comprising a pivoting arm supporting the grapple device, the pivoting arm being rotatably attached to the pivoting frame around an axis extending in the width direction of the vehicle body, and supporting the grapple device above the pivoting frame.

3. A felling vehicle as described in claim 1, further comprising a pivoting arm supporting the grapple device, the pivoting arm being rotatably attached to the pivoting frame around an axis extending in the fore-and-aft direction of the vehicle body, and supporting the grapple device above the pivoting frame.

4. A felling work vehicle as described in claim 2 or 3, wherein the grapple device is attached to the pivoting arm via a flexible support mechanism, and the flexible support mechanism allows the grapple device to rotate relative to the pivoting arm about a predetermined axis.

5. A felling work vehicle as set forth in claim 4, wherein said flexible support mechanism elastically supports said grapple device so as to allow said grapple device to rotate about a predetermined axis relative to said pivot arm.

6. A felling vehicle as claimed in claim 2 or 3, wherein the pivoting arm is configured to be extendable so that the grapple device is separated from the pivoting frame.

7. A felling work vehicle as set forth in claim 1, wherein said cutting device is constructed so as to cut the standing tree to be felled below said pivot axis.

8. A felling vehicle as claimed in claim 1, further comprising a torque application device which, when felling a tree cut by the rotation of the pivoting frame, applies a torque to the pivoting frame in a direction opposite to the direction in which the tree falls, thereby slowing down the speed at which the tree falls.

9. A felling vehicle as claimed in claim 1, further comprising a winch for assisting the travelling device in traveling, the drum of which is adapted to pay out or wind up the wire rope in synchronization with the travelling device.

10. A felling vehicle as set forth in claim 1, further comprising a prime mover that generates power to operate said traveling device, said prime mover being supported on said vehicle body so as to be rotatable about a substantially horizontal axis.

11. A felling work vehicle as claimed in claim 1, wherein said cutting device is a chain saw rotatably mounted on said pivoting frame.

12. A felling vehicle as described in claim 2, wherein the grapple device is configured to be able to hold the tree to be felled while maintaining the rotating frame approximately parallel to the slope, even when the tree is growing on an uphill or downhill slope, and the cutting device is configured to cut the tree within a plane approximately parallel to the rotating frame.

13. A felling vehicle as described in claim 3, wherein the grapple device is configured to be capable of holding a tree to be felled even when the tree is growing on a slope that inclines to the left and right of the vehicle body, and the cutting device is configured to cut the tree held by the grapple device.

14. A felling vehicle as described in claim 3, wherein the grapple device is configured to be able to hold a tree to be felled even when the tree is growing on a slope that is inclined in the fore-and-aft direction of the vehicle body and also in the left-right direction of the vehicle body, and the cutting device is configured to cut the tree held by the grapple device.

Images